Hi all,
I am still working on this project as and when I get a chance or at least when work, sleep and beer don't get in the way
Tonight I have bolted the four main bits of the chassis back together prior to re- connecting all the inter panel wiring. The wiring will take a while as there is plenty of room for error.
There is a tag strip on the top chassis which carries the interlace filter components which I am just about to refurbish. There is a diode which according to the circuit is type Q1/5 about 1/2 inch long, 3/8 wide with a green and a black band. It measures open circuit.
Am I correct in thinking this would be a germanium type and I can use an OA91? Does anyone have any information about it?
I also experimented with re- forming the main smoothing cap. I tried the 100 mfd section first. Using a 280V supply, I limited the current with a resistor to about 5ma. Fairly quickly the current fell to about 1ma, so I decided to leave it on overnight. In the morning, the current had actually increased back to 5ma which I felt was not a good sign.
The end result after further messing about was when it was directly connected to the supply, it drew a steady 2ma. When it was disconnected, the voltage fell pretty quickly (my meter only draws 30 micro amps).
So I'm not sure I really trust it to do it's job either very well or very reliably.
I don't fancy it going short when I am using the set on a regular basis.
I have therefore, rather reluctantly I must say, decided to re-stuff it with modern caps.
I have never done such a thing before, but then I have not gone to this level with a restoration before!
My plan is to cut it under the clamp and then remove the innards. When I know exactly what the internal dimensions of the can are, I can select the replacement caps. Space will be very tight as there is a 400mfd, a 100mfd and a 16mfd in the same can! Also the 100 mfd needs to have a decent ripple current rating. Suitable replacements are actually quite large.
Anyway, that's it for tonight. I'll post some more pictures soon.
Cheers Nick